TW201607778A - Fluid ejection structure - Google Patents

Abstract

A fluid ejection structure can include thermal resistors, a substrate, layers on the substrate, wherein said layers can include a region proximate to the resistor that has reduced field oxide.

Description

Fluid injection structure

The present invention relates to a fluid ejection structure.

Background of the invention

The fluid ejection structure dispenses droplets based on the input digital data. A typical fluid ejection structure includes a nozzle array or the like that can dispense a fluid in a nozzle plate. The array of nozzles can be arranged at a higher resolution and can be dispensed with high precision. Certain fluid injection structures are provided with thermal resistors or the like that are capable of ejecting fluid out of the nozzles adjacent to the nozzles. To create an eruption event with a thermal resistor, a current will pass through the resistor, which will rapidly heat and vaporize a thin layer of fluid near the resistor. The liquid-to-steam transition creates an expanded bubble in the firing chamber adjacent the fluid body and ejects a fine droplet through the nozzle. An insulating oxide layer will typically be present underneath the resistor to direct heat to the fluid in the firing chamber.

According to an embodiment of the present invention, a fluid ejection structure is specifically provided, comprising: a plurality of thermal resistors arranged at a pitch of at least about 300 per turn; a substrate; and a plurality of layers on the substrate, including a a heat dissipating region is adjacent to the resistor between each resistor and the substrate; and an adjacent layer region is adjacent to the heat dissipating region, the adjoining layer region comprising field oxide having on the substrate a first thickness; wherein the reduced field oxide has a reduced thickness between about 0% and 80% of the first thickness in the heat sink region.

1, 101, 201, 301, 401, 501‧‧‧ fluid injection structure

3, 103, 203, 303, 403, 503‧‧‧ Thermal resistors

5, 105‧‧‧Ejection chamber

7‧‧‧film layer

9, 109, 309, 409, 509‧‧‧ substrates

11, 111, 211, 311, 411, 511‧‧‧ fluid feeders

13, 13A, 113, 213, 313, 313A, 413, 513, 513A‧ ‧ field oxide layer

15, 215, 315, 415, 515‧‧ ‧ heat dissipation area

17, 217, 317, 417, 517 ‧ ‧ adjacent layers

23, 223, 323, 423, 523‧‧‧ slot area

107, 307, 407, 507‧ ‧ cascading

119‧‧‧Nozzle plate

121‧‧‧Nozzles

200‧‧‧Printing head 匣

227‧‧‧Line array

229‧‧ ‧ field oxide strip

335, 435, 447, 535, 547‧‧ ‧ oxide layer

337, 437, 443, 445, 537‧‧‧ conductive layers

431, 533‧‧‧p well area

433, 531‧‧‧n well area

441‧‧‧Thermal resistor material layer

449‧‧‧ gate layer

I‧‧‧corresponding part

T‧‧‧first thickness

T2‧‧‧ thickness

For the purpose of explanation, certain examples constructed in accordance with the present disclosure will now be described with reference to the accompanying drawings in which: FIG. 1 shows a schematic diagram of a section of a fluid ejection structure; FIG. 2 shows a fluid ejection structure. FIG. 3 is a schematic view showing a cross section of another example of a fluid ejection structure; FIG. 4 is a schematic view showing a cross section of another example of a fluid ejection structure; and FIG. 5 is a schematic view showing a fluid ejection. A cross-sectional view of still another example of the structure; and FIG. 6 shows a cross-sectional view of still another example of a fluid ejection structure.

Detailed description

In the following detailed description, reference will be made to the drawings. The examples in the description and drawings are to be considered as illustrative and not restrictive. Numerous examples can be obtained from the following description and drawings, with modifications, combinations or variations of the various elements.

In the present disclosure, the fluid ejection structure will be discussed. A typical fluid ejection structure is a print head. The fluid ejection structure of the present disclosure can be formed An integrated print head or a portion of the print head of a stationary or semi-permanent printer. A typical fluid contains ink. Other examples of fluid ejection structures include printheads for three-dimensional printers and high precision digital titration devices. Examples of other fluids include three-dimensional printing fluids, such as three-dimensional printing agents, including powder binding enhancers and inhibitors, and fluids for digital titration, such as for testing, assembly, and/or formulation pharmaceuticals, Biomedical, scientific or legal use. The fluid ejection structure can be part of a completed device or can form an intermediate article. The fluid ejection structure of the present disclosure is provided with a thermal resistor or the like to emit the droplets. In one example the resistors are thermal inkjet (TIJ) resistors. These resistors can be used for any high precision dispensing applications such as 2D printing, 3D printing and digital titration.

A fluid ejection structure can include at least one oxide layer disposed over a substrate or conductive bead. The oxide layers have electrical and thermal insulating properties. An oxide layer adjacent to a thermal resistor can thermally isolate the thermal resistor during an ejection event, resulting in a rapid and energy efficient eruption event. This can result in a low starting energy for one of the resistors.

When a suitable current is applied to the resistor, the resistor and the fluid near the interface with the resistor will rapidly heat up, for example, applying a pulse width range of about 0.02 to 200 microseconds, wherein the amount of time may depend on Resistor resistance, resistor size, aspect ratio, fluid type, droplet size, and resistor spacing. Fluid close to the resistor turns into steam and creates an expanding bubble. The progressively expanding vapor bubble forces some of the fluid out of a droplet nozzle to create an ejected droplet. After this eruption event, the local pressure caused by the vapor bubble is reduced. This event can be called Shrink for bubbles. When the bubble collapses, there is a new fluid in the adjacent fluid feed tank that is drawn back into the firing chamber. After the eruption event, if the resistor has not cooled sufficiently, a scorch effect or small-scale reboiling may occur on the surface of the hot resistor as the fluid flows back into the firing chamber. . If the fluid is ink, it sometimes happens that solids in the ink form deposits on or near the resistor, which may cause a thermal suppression film that can negatively impact the performance of the resistor and nozzle. For example, the resistor or its protective layer, such as germanium, will be more susceptible to oxidation if the fluid repeatedly contacts a thermal resistor. In addition, more time delays at higher temperatures may have a negative effect on these resistors, such as shorter resistor functional life. And the resistor or other chemical and physical properties of the fluid are also negatively affected by a slow cooling. Therefore, faster cooling of one of the resistors prevents some of the aforementioned negative effects. Although the insulating oxide layer near the resistor contributes to a lower starting energy during the firing, too much insulation slows the cooling of the resistor after the eruption.

Fig. 1 schematically shows a section of an example of a portion of a fluid ejection structure 1 in a front elevational view. The fluid ejection structure 1 comprises a thermoelectric assembly 3. The fluid ejection structure 1 of the present disclosure is provided with an array of the thermal resistors 3 and the like. For example, the thermal resistors 3 are arranged in at least a linear array, such as a plurality of parallel linear arrays. The linear array can have a pitch of at least about 300 resistors, at least about 590 resistors per turn, for example about 600 nozzles per turn.

Each of the thermal resistors 3 can be placed in or near a corresponding firing chamber 5. The thermal resistor 3 is provided on at least one of the film layers 7. At least one Layer 7 is attached to a substrate 9. A fluid feed tank 11 is provided in close proximity to the resistor 3 and the at least one layer 7. The fluid feed tank 11 is capable of feeding fluid to the firing chamber 5.

The at least one layer 7 comprises at least one oxide layer. The at least one oxide layer may comprise a field oxide layer 13. The at least one layer 7 can be divided into two zones 15, 17. A region 15 of the at least one layer 7 is between the resistor 3 and the substrate 9, referred to herein as the heat sink region 15. An area adjacent to the heat dissipation zone 15 is referred to herein as the abutment zone 17. As will be explained in the present disclosure, heat dissipation enhanced by the plurality of layers 7 or the like may occur in the heat dissipation region 15. Heat dissipation can also occur outside of the heat sink region 15, albeit to a lesser extent. In an operational state, the fluid exiting structure 1 will eject droplets in a downward direction, so that the heat dissipating region 15 will extend over the resistor 3. In FIG. 1, the heat dissipation region 15 extends directly under the resistor 3. For example, the fluid ejection structure of Figure 1 is in a manufacturing or delivery orientation that can be used for illustrative purposes. The heat dissipation region 15 can be defined as a layer region that defines a shortest distance between the resistance region 3 and the substrate 9 by directly projecting the thermal resistor 3 on the plurality of layers 7 to the substrate. 9 is shown up as shown by the dotted line. An adjacent layer region 17 is tied in close proximity to the heat sink region 15. In the illustrated example, the adjoining layer region 17 is disposed on a side of the heat dissipating region 15 opposite to the fluid feed channel 11. On the other side of the heat dissipating region 15, a groove region 23 of the layers 7 is provided. The groove region 23 is bounded by the fluid feed groove 11. The heat sink region 15 may be centered below/above the resistor and may have less oxide insulating layer or a smaller total oxide thickness than the adjacent region 17 and the trench region 23.

In the cross section shown, a field oxide layer 13, 13A is Above the substrate 9. A field oxide layer 13 having a first thickness T is disposed over the substrate 9 in the adjacent layer region 17. In the heat sink region 15, the field oxide is reduced relative to the adjacent regions. In one example, the heat sink 15 is provided with a field oxide 13A having a reduced thickness T2. In another example, the heat sink 15 is free of field oxides. In the present disclosure, "reduced field oxide" means that any field oxide in the heat dissipation region 15 has a characteristic fine structure less than the adjacent region, and has a thickness T2 of about 0 of the thickness T of the adjacent region. % to 80%, 0% to 70%, 0% to 60%, 0% to 50%, 0% to 40%, 0% to 30%, or 0% to 20%. When the reduced field oxide is 0% of the thickness of the adjacent region, the heat sink region 15 is free of field oxide. In other examples, the field oxide 13A is reduced to between 20% and 80% of the thickness T of the adjacent region. An example of the reduced but not completely omitted field oxide field 13A is shown by a dashed line.

For example, a strip oxide, rectangular or circular field oxide field may be reduced using a suitable tantalum processing technique, which may include etching after applying a corresponding strip, rectangular or circular shaped shell. In one example, a tantalum nitride (SiN) film will be deposited, photopatterned, and etched, and then the field oxide will grow where the SiN film is not present. For example, the SiN film is present in the heat dissipation region 15. The SiN will be etched and the field oxide will remain in the adjacent layer region 17. In another example, the field oxide is grown throughout the heat sink region 15 and the adjacent region 17 and the trench region 23, but is thereafter etched into a thinner layer 13A in the heat sink region 15 and the trench region 23.

The field oxide layer 13 having a first thickness T terminates in the edge of the heat sink region 15 in the figure. In other examples, the field oxide layer 13 can Just ending outside the heat dissipating region 15, or just in the heat dissipating region 15, as long as at least a portion of the substrate 9 in the heat dissipating region 15 is free of the field oxide layer 13. The field oxide 13 is also disposed above the substrate 9 in the trench region 23. In the figure, the field oxide 13 in the trench region 23 terminates along the fluid feed channel 11. After the layers 7 have been placed on the substrate 9, the feed channels 11 can be etched through the layers 7. The average thickness of one of the summed oxide layers in the heat sink region 15 may be thinner than the average thickness of one of the summed oxide layers in the adjacent layer region 17 and the trench region 23.

It has been found that some of the oxide in the heat sink region 15 adjacent to the resistor 3 can be removed or omitted to allow the resistor to cool down relatively quickly before the fluid is drawn into the firing chamber 5, yet A sufficient insulation can be maintained during the eruption event, i.e., the starting energy is not substantially affected. The field oxide 13, and again an electrical insulator, has a high thermal insulating property. By reducing the field oxide thickness in the heat sink. Heat can be dissipated to the substrate 9 more quickly. With the enhanced heat dissipation, the negative effect of slow cooling of a resistor can be suppressed. In a different case, reducing the field oxide near the resistor 3 can improve resistor life, resistor reliability, and nozzle robustness without substantially affecting the activation energy of one of the resistors 3. In still another example, because the resistor 3 will cool more quickly, a larger range of fluid can be ejected with the fluid exiting structure 1.

Fig. 2 schematically shows another example of a fluid ejection structure 101 in another cross-sectional view. For example, a portion I of FIG. 2 corresponds to the diagram of FIG. 1. In one example, the fluid ejection structure 101 of Figure 2 forms a portion of a row of printheads. The fluid injection structure 101 includes a fluid feed tank 111, a nozzle chamber 105, and the like. The nozzle 121 is in a nozzle plate 119. The fluid feed tank 111 is opened in the two firing chambers 105, which are open to the nozzles 121 and the like. Thermal resistors 103 are provided in each of the firing chambers 105 to direct fluid out of the nozzles 121. Adding layers, such as tantalum carbide, tantalum nitride, and/or germanium, can cover each resistor 103 to provide protection during manufacturing to avoid chemical and physical attack and electrical isolation, and to avoid such ink and eruption events.

The resistor 103 is supported by a respective stack 107 on a substrate 109. The fluid feed slot 111 will pass through the stack 107 and the substrate 109. The stack 107 includes a field oxide layer 113. As shown, the field oxide in the layer region that is close to the resistor 103 is reduced compared to the field oxide 113 in the absence of a reduced layer region. In the example shown, the field oxide system close to the resistor 103 is reduced to zero. In another example (not shown), some of the field oxide is present adjacent to the resistor 103 with a reduced thickness relative to the thickness of the field oxide layer 113 in the adjacent layer region.

FIG. 3 shows a simplified diagram of an integrated printhead cartridge 200 including a fluid ejection structure 201. The crucible 200 can further include a fluid sump capable of supplying fluid to a fluid feed tank 211. The fluid ejection structure 201 of FIG. 3 may correspond to one of the sections III-III of the fluid ejection structure of FIG. The fluid ejection structure 201 includes a linear array 227 of the thermal resistors 203 and the like, and each of the thermal resistors 203 is disposed adjacent to at least one of the respective nozzles. Since the thermal resistors 203 are not directly exposed to the cross section, the thermal resistors 203 are shown in dashed lines. In the illustrated example, two parallel linear arrays 227 of linear resistors 203 are provided along a single fluid feed slot 211. The nozzles are also not visible in this section and are arranged in a corresponding linear array. For example, a plurality of fluid feed slots 211 and one A double amount of parallel resistor array 227 can be provided. For example, a plurality of color sump can be provided in an integrated print head, wherein each color sump is fluidly coupled to at least one fluid feed 211.

In one example, the thermal resistor and/or nozzle array has a spacing of at least about 300 resistors 203 and/or nozzles per turn. In another example, the thermal resistor and/or nozzle can have a pitch of at least about 590 resistors 203 and/or nozzles per turn, such as at least about 600 resistors 203 and/or nozzles per turn, such as each turn. Approximately 600 resistors 203 and/or nozzles. In yet another example, the spacing can be up to about 2400 resistors 203 and/or nozzles per turn.

A fluid feed slot 211 is disposed in parallel between the resistor arrays 227. The fluid feed tank 211 is capable of receiving fluid from the sump. The field oxide layer 213 extends on both sides of the fluid feed slot 211 and terminates in the fluid feed slot 211. The fluid feed slot 211 can be etched therethrough after the layers are deposited. The field oxide 213 between the resistors 203 and the substrate has been reduced near the respective resistor arrays 227 in the heat sink region 215. The field oxide 213 will extend on either side of the resistors 203, such as in a trench region 223 along the fluid feed slot 211, and in a contiguous region 217 on the opposite side of the heat sink region 215.

The field oxide strips 229, which are continuously reduced in the illustrated example, will extend across the resistor array 227 and extend through each of the heat sink regions 215 of each resistor 203. Each of the reduced field oxide strips 229 can be free of field oxides or can have fewer field oxides than adjacent regions having a reduced field oxide. On both sides of the fluid feed tank 211, a reduced field oxide strip 229 will extend parallel to the fluid feed slot 211. In one example, the field oxide is patterned by first depositing and patterning a tantalum nitride (SiN) film such that the SiN is stretched across the resistor array 227. The field oxide erbium is grown where the SiN is absent and the SiN is etched away. Thus, a rectangular less field oxide strip 229 can be defined to allow for better heat dissipation.

FIG. 4 shows a simplified diagram of another example of a section of a fluid ejection structure 301. The fluid ejection structure 301 includes a thermal resistor 303 disposed over a stack 307 that is disposed over a substrate 309. In the cross-sectional portion shown, the stack 307 and the substrate 309 terminate in a fluid feed slot 311 that is etched through the stack 307 after the stack 307 is deposited. The stack 307 includes a heat sink region 315 adjacent the resistor 303 that is defined by projecting the resistor 303 on the stack 307 straight onto the substrate 309, as shown by the dashed lines in FIG. A slot region 323 extends on one side of the heat dissipation region 315 between the heat dissipation region 315 and the fluid feed slot 311, and an adjacent layer region 317 extends on an opposite side of the heat dissipation region 315.

The stack 307 comprises at least one oxide layer 335, i.e., at least one layer of which is calculated from the substrate 309. In one example, the oxide layer 335 is not a field oxide layer 313. The oxide layer 335 extends through the adjacent regions 317, the regions 315 and the trench regions 323, respectively, and terminates in the fluid body trench 311. The fluid feed channel 311 has been etched through the layers 307, thus defining the termination point of the field oxide layer 313 and the oxide layer 335. The oxide layer 335 electrically and thermally insulates the resistor 303. The stack 307 includes a conductive layer 337. The oxide layer 335 is disposed above the conductive layer 337. The conductive layer 337 contains a metal component or may be substantially composed of a metal component. The conductive layer 337 will Extending through the adjacent layer region 317, and at least partially in the heat sink region 315. In one example, it will span the entire heat sink zone 315. The conductive layer 337 can be part of a power circuit. The conductive layer 337 can have thermal conductivity properties which make it suitable as a heat dissipating material. The conductive layer 337 can function as one of the resistors 303 to dissipate heat to cool down after an eruption event.

Field oxides 313, 313A are disposed above the substrate 309. At least a portion of the field oxide 313 has been removed or removed from the substrate 309 in the heat sink region 315. In one example, the substrate 309 has no field oxide in the heat sink region 315. In another example, a field oxide field 313A having a reduced field oxide thickness relative to the contiguous region 317 is provided in the heat sink region 315 as indicated by the dashed line. By locally removing the field oxide 313, heat can be dissipated via the conductive layer 337 and the substrate 309 after eruption, and the oxide layer 335 provides sufficient isolation during the pulse/eject event.

FIG. 5 shows a cross section of an exemplary fluid ejection structure 401. The fluid ejection structure 401 includes a substrate 409 and a stack 407 above the substrate 409. A layer of thermal resistor material 441 is placed on top of the stack 407. In one example, the thermal resistor material layer 441 comprises tungsten germanium nitride (WSiN). The active portion 403 of one of the thermal resistor material layers 441 will hereinafter be referred to as a resistor 403. A heat sink region 415 between the resistor 403 and the substrate 409 can be defined by projecting the resistor 403 onto the substrate 409, for example, at an approximately right angle. An adjacent layer region 417 extends adjacent to the heat sink region 415 on the opposite side of the fluid feed slot 411. A slot region 423 will cover a stacking zone between the heat sink region 415 and the fluid feed slot 411.

The thermal resistor material layer 441 is disposed over the first and second conductive layers 443, 445, respectively. The first and second conductive layers 443, 445 are resistor power lines that can apply a voltage across the active resistor portion 403 of the resistor material layer 441. In the figure, the first and second conductive layers 443, 445 are the same layer, and a portion of the layer 443 is removed where the resistor 403 is provided. In one example, the first and second conductive layers 443, 445 comprise an aluminum copper (AlCu) alloy. The first and second conductive layers 443, 445 may extend on opposite sides of the resistor 403. The resistor 403 and the first and second conductive layers 443, 445 are disposed above a first oxide layer 435. The first oxide layer 435 comprises ethyl orthosilicate (TEOS) and/or high density plasma TEOS. The first oxide layer 435 extends in the adjacent layer region 417, the heat dissipation region 415, and the trench region 423. The first oxide layer 435 terminates at the fluid feed slot 411. The first oxide layer 435 is disposed above a third conductive layer 437. The third conductive layer 437 contains a metal component. In one example, the third conductive layer 437 comprises titanium (TiN) and AlCu. The third conductive layer 437 can be part of a power circuit, such as a power ground or power supply loop. The third conductive layer 437 extends from the adjacent layer region 417 into the heat dissipation region 415. In the illustrated example, the third conductive region 437 will extend beyond the heat sink region 415 in the trench region 423 and terminate at a distance from the fluid feed slot 411. In the trench region 423, the first oxide layer 435 and the field oxide 413 will isolate the third conductive layer 437 from the fluid in the fluid feed slot 411. The third conductive layer 437 is disposed above a second oxide layer 447. In one example, the second oxide layer 447 comprises TEOS and borophosphonate (BPSG). In the illustrated example, the second oxide layer 447 will extend and terminate in the adjacent layer region 417. The heat dissipation area 415 There is no such second oxide layer 447. The second oxide layer 447 is disposed over the field oxide layer 413. The field oxide layer 413 will cover the substrate 409. In this example, the field oxide layer 413 extends in the adjacent layer region 417 and in the trench region 423. In this example, the field oxide layer 413 will terminate outside of the heat sink region 415, respectively in the adjacent region 417 and the trench region 423. The substrate 409 has no field oxide in the heat sink region 415. A gate layer 449 is disposed over the substrate 409 in the heat dissipation region 415 to extend the heat dissipation region 415. The gate layer 449 can comprise polysilicon and gate oxide. The polysilicon can act as a protective etch stop and the gate oxide provides electrical insulation. The gate layer 449 terminates in the adjacent layer region 417 and in the trench region 423. The gate layer 449 is partially disposed above the field oxide layer 413 in the adjacent layer region 417, adjacent to an edge and partially above the field oxide layer 413, in the trench region 423, near a The opposite edge. The third conductive layer 437 is disposed above the gate layer 449 in a portion of the adjacent layer region 417, the heat dissipation region 415, and the trench region 423. The second oxide layer 447 and the gate layer 449 can isolate the third conductive layer 437 from the field oxide layer 413 and the substrate 409.

The substrate 409 can include a doped n-well region 433 having a higher electrical resistance that provides added electrical isolation between the conductive substrate 409 and the third conductive layer 437. The n-well region 433 can be electrically connected to a ground source or electrically floating. A doped n well region 433 will span the heat sink region 415. For example, the doped n well region 433 will extend from the adjacent layer region 417 into the heat sink region 415 and into the trench region 423, and terminate in an adjacent layer region 417 at an edge and terminate at an opposite edge. In the groove area 423. The doped n well region 433 spans the entire surface where the gate layer 449 is disposed on the substrate 409, and the edges thereof terminate in a different Field oxide layer 413.

A P-well 431 is provided on both sides of the n-well zone 433. Field oxide 413 can be disposed over the p-well regions 431. For example, the p-well regions 431 extend over a portion of the oxide layer 413 and another oxide layer 435, 437 stacked over the substrate 409. For example, in the adjacent layer region 417, the p-well region 431 will exist where a field oxide layer 413 and a second oxide layer 447 are stacked above the substrate 409. For example, the other p-well region 431 may be present in the trench region 423 where a field oxide layer 413 and a first oxide layer 435 are stacked over the substrate 409.

The n-well region 433 electrically isolates the third conductive layer 437 from the p-well regions 431. To further enhance the electrical isolation of the third conductive layer 437, the second oxide layer 447 terminates on the gate layer 449, and the gate layer 449 terminates on the field oxide layer 413 and is in the second oxide. Below the layer 447, in the adjacent layer region 417. On the opposite side, in the trench region 423, the gate layer 449 terminates on the field oxide layer 413, and the n-well region 433 extends further in the trench region 423.

The exemplary fluid ejection structure 401 can provide an appropriate eruption event insulation and post-emission event cooling. The first oxide layer 435 thermally insulates the resistor 403 during the ejection event, and the removed and reduced second oxide layer 447 and the reduced field oxide layer allow heat to be transferred to the post-ejection The substrate 409. The third conductive layer 437 assists in conducting heat to the substrate 409.

FIG. 6 shows a simplified diagram of a cross section of another exemplary fluid ejection structure 501. The fluid ejection structure 501 includes a substrate 509, and a stack 507 is over the substrate 509. A thermal resistor 503 is provided in the stack 507 Top, for example, as part of a layer of thermal resistor material (not shown), coupled to the power line, can apply a voltage to the resistor 503. A heat sink region 515 between the resistor 503 and the substrate 509 can be defined by projecting the resistor 503 onto the substrate 509, for example, at an approximately right angle. An adjacent layer region 517 extends adjacent to the heat sink region 515 on the opposite side of the fluid feed slot 511. A groove region 523 covers a stacked region between the heat dissipation region 515 and the fluid feed groove 511.

The resistor 503 is disposed above a first oxide layer 535. The first oxide layer 535 extends in the adjacent layer region 517, the heat sink region 515, and the trench region 535. The first oxide layer 535 terminates in the fluid feed slot 511, wherein the fluid feed slot 511 is etched through the layers 507 after the layers 507 are deposited. The first oxide layer 535 is disposed above a conductive layer 537. The conductive layer 537 can be part of a power circuit, such as a power ground or power supply circuit. The conductive layer 537 will extend from the adjacent layer region 517 into the heat sink region 515. In the illustrated example, the conductive layer 537 will overtake the heat sink region 515 in the trench region 523 and terminate at a distance from the fluid feed slot 511. In the trench region 523, the first oxide layer 535 isolates the conductive layer 537 from the fluid in the fluid feed slot 511. The conductive layer 537 is disposed above a second oxide layer 547. In the illustrated example, the second oxide layer 547 extends and terminates in the adjacent layer region 517. The heat dissipation region 515 is free of the second oxide layer 547. The second oxide layer 547 is disposed over the field oxide layers 513, 513A.

The field oxide layer 513 covers the substrate 509. In this example, the field oxide layer 513 extends in the adjacent layer region 517, the heat sink region 515, and the trench region 523. In the adjacent layer region 517, the field oxide layer 513 has A first thickness T. In the heat dissipation region 515 and the groove region 523, the field oxide layer 513A has a thickness T2 which is reduced with respect to the first thickness T. In the illustrated example, the reduced field oxide field 513A extends into the contiguous region 517 and terminates outside of the heat sink region 515 at the point where the second oxide layer 547 terminates. In the trench region 523, the reduced field oxide field 513A will terminate in the fluid feed slot 511. The reduced field oxide field 513A can have a thickness T2 of about 70% or less, or about 60% or less, or about 50% or less, or about 40% of the reduced thickness T1. Or less. Here, no gate layer or etch stop layer is provided over the substrate in the heat dissipation region 515. The substrate 509 includes a doped p well region 533 that overlaps the heat sink region 515 and projects into the adjacent layer region 517 and the trench region 523. For example, the p-well 533 will extend along and beyond the entire reduced field oxide field 513A.

In one example, the fluid exit structure 501 does not have polysilicon as a protective etch stop. A dry etch process can be used to remove a pre-exposed or patterned second oxide layer 547. For example, when the second oxide layer 547 is etched to remove a portion of the second oxide layer 547, the field oxide is exposed to the same etching process used to remove the second oxide layer 547. The field oxide can thus be etched and thinned, which is not protected by any polysilicon. After the final etching, the thickness T2 of the field oxide 513 adjacent to the second oxide layer 547 may be 80% or less, 70% or less, 60% or less of the original field oxide thickness T. Less, 50% or less, 40% or less, 30% or less, or 20% or less. In one example, the reduced field oxide field 513A has a thickness T2 between about 20% and about 80% of the adjacent thickness T. In one example, the reduced field oxide field 513A Termination is at approximately the same point as the second oxide layer 547. Therefore, the reduced field oxide field 513A extends from the end point of the second oxide layer 547 to the fluid feed slot 511. The reduced field oxide field 513A is reduced to be thick enough to provide electrical isolation between the conductive layer 537 and the substrate 509. Therefore, the n-well doped region 531 is not required below the reduced field oxide field 513A.

The exemplary fluid ejection structure 501 provides an appropriate eruption event insulation and post-emission event cooling. The first oxide layer 535 thermally insulates the resistor 503 during the erupting event, and the reduced second oxide layer 547 and field oxide 513A allow heat to be transferred to the substrate 509 after eruption. The conductive layer 537 and the reduced field oxide 513A assist in conducting heat to the substrate 509.

In a different embodiment of the present disclosure, the oxide layer adjacent the resistor is thick enough to be insulated during an eruption event and is thin enough after the eruption and after the fluid is ejected from a firing chamber. Heat can be dissipated to the substrate to cool the resistor before refilling the firing chamber. In the different examples of the present disclosure, heating and cooling events can occur over a range of pulse widths ranging from less than 1 microsecond to several (or tens of) microseconds. In various embodiments of the present disclosure, all of the layers may have a thickness in the range of from about 10 to about 2000 nm. For example, a field oxide layer can have a thickness between about 200 and about 1000 nm, such as between about 400 and about 700 nm.

Field oxides can be deposited and reduced using appropriate integrated circuit (IC) wafer fabrication techniques, such as coatings that block field oxide growth by patterning, or photolithography and dry or wet etching techniques. . In a different example, the reduced field oxide field thickness T2 can be about the adjacent thickness T. Between 0 and 80%. For example, the reduced field oxide thickness is 0% when completely ablated (eg, prevented growth), or greater than 0% when only partially removed, for example, up to 20%, 30%, 40 %, 50%, 60%, 70% or 80%. Other layers may also be routed or omitted to provide sufficiently strong electrical insulation and isolation, or to provide a chemical or physical etch stop during fabrication of the structure. The enhanced thermal properties of such exemplary fluid ejection structures can at least somely inhibit thermal induced problems, including chemical or physical degradation of the protective layer of a resistor, and contaminants on the resistor. Deposition. Using certain ranges of the present disclosure, a preferred and long life resistor can be obtained and a wide range of fluids can be ejected.

401‧‧‧ fluid injection structure

403‧‧‧Thermal resistor

407‧‧‧ cascading

409‧‧‧Substrate

411‧‧‧ fluid feeder

413‧‧ ‧ field oxide layer

415‧‧‧heating area

417‧‧‧Adjacent area

423‧‧‧Slots

431‧‧‧p well area

433‧‧‧n well area

435, 447‧‧‧ oxide layer

437, 443, 445‧‧‧ conductive layer

441‧‧‧Thermal resistor material layer

449‧‧‧ gate layer

Claims (15)

A fluid ejection structure comprising: a plurality of thermal resistors arranged at a pitch of at least about 300 per turn; a substrate; and a plurality of layers on the substrate, comprising a heat dissipation region close to the resistor, at each resistor Between the substrate and the substrate; and an adjacent layer region adjacent to the heat dissipation region, the adjacent layer region comprising a field oxide having a first thickness on the substrate; wherein the reduced field oxide is in the heat dissipation region, There is a reduced thickness between about 0% and 80% of the first thickness. The fluid ejection structure of claim 1, wherein the at least one thermal resistor material layer comprises the plurality of thermal resistors, wherein the heat dissipation region and the adjacent layer region are stacked on the substrate and the thermal resistor material layer It consists of several layers. The fluid ejection structure of claim 1, comprising at least one fluid channel and at least one thermal resistor array parallel to the fluid channel, wherein the reduced field oxide field spans the entire thermal resistor array. The fluid ejection structure of claim 1, wherein: the adjacent layer region comprises at least one oxide layer different from the field oxide in the adjacent layer region; and the number of layers does not have the oxide layer in the heat dissipation region. The fluid ejection structure of claim 1, wherein an average thickness of one of the oxide layers in the heat dissipation region is thinner than in the adjacent layer region. The fluid ejection structure of claim 1, comprising a conductive via layer comprising a metal component extending from the adjacent layer region into the heat dissipation region. The fluid ejection structure of claim 6, wherein the conductive layer is part of a power circuit. The fluid ejection structure of claim 1, wherein the heat dissipation zone has no field oxide. The fluid ejection structure of claim 8, wherein at least one of the gate layers is disposed between the substrate and the conductive layer. The fluid ejection structure of claim 8, wherein the substrate comprises an n-well region spanning the heat dissipation region. The fluid ejection structure of claim 1, wherein a field oxide system having a reduced layer thickness is provided in the heat dissipation region, and no gate layer is disposed in the heat dissipation region. The fluid ejection structure of claim 11, wherein the substrate comprises a p-well region spanning the heat dissipation region. The fluid ejection structure of claim 1, comprising: at least one firing chamber adjacent to the at least one of the resistors; a fluid feed channel leading to the firing chamber; wherein the adjacent layer region is opposite to the fluid feed slot and adjacent to the A heat sink region extends; and a slot region is provided between the heat sink region and the fluid feed slot, the trench region containing field oxide covering the substrate and terminating in a fluid feed slot. The fluid ejection structure of claim 1, wherein the adjacent layer region further comprises: a thermal resistor material layer; at least the dioxide layer is different from the field oxide; and a power circuit layer; and the heat dissipation region further comprises: at least One oxide layer is less than the adjacent layer region; the power circuit layer; and a gate oxide layer. A fluid ejection structure comprising: at least one layer of thermal resistor material comprising a thermal resistor array having a pitch of at least about 300 per turn; a substrate; and at least one oxide layer in a layer of thermal resistor material and Between the substrates, the at least one oxide layer comprises: a reduced field oxide layer field disposed over the substrate in a region proximate to the resistor to enhance cooling of the resistor after erupting; A field oxide layer having no reduction is disposed over the substrate outside of a region proximate to the resistor.